help me with math:{?

Question

a glass and mirror store is selling mirrors with frames ...
the store charges 10 cents for each square inch of mirror,and 25 cents for each linear inch of frame..
show that a 20 inch by 30 inch mirror should cost 85.00 $
if there was a mirror that measured 40 inches on one side what would the other measurement be if the price were still 85$?
write an equatio that determines the price (P)given a length (L) and a width (W)
solve this equation for (L)?????


please i really need help...becaus im no good in math..:(

Answer 1

20 inch by 30 inchframe
area=600 sq.inch
charge=600*0.10=$60
perimeter=100 inch
charges=100*0.25=$25
so total charges=$85
P=(L*W)*0.10+2(L+W)0.25 in dollars

Answer 2

Ok..for the first one, draw a picture of a rectangle. The two longer sides are 30 in so write 30 on both those lines. The two shorter are 20, so write 20. 30 inches x 20 inches is 600 inches, which is your square footage. Multiply that by 10 cents to get $60. Now add the sides of the frame: 30 + 20 + 30 + 20. That makes 100. Multiply 100 by $.25. There is $25. Add $60 + $25 to get the $85.

Answer 3

perimeter = 2 x (20+30) = 100inch
area = 20 x 30 = 600 square inch
cost of mirror = 10 (600) + 25 (100) = 8500 cents = $ 85
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perimeter = 2 x (40 + L) inch
area = 40 L square inch
cost = 10 (40 L) + 25 (2 x (40 + L)) = 8500
or 400L + 2000 + 50L = 8500
or 450 L = 6500
or L = 14.44 inch
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P = 10 (L * W) + 25 (2 * (L+W))
P = 10 LW+ 50L + 50W